Resinous materials and process of preparing the same



1946 F. w. KRESSMAN- EI'AL 2,413,326

RESINOUS MATERIAL. AND PROCESS .OF PREPARING THE SAME Filed Jan. 5, 1942 @Zi i W ATTORNEYS.

Patented Dec. 31, 1946 RESINOUS MATERIALS AND PROCESS OF PREPARING THE SAME Frederick W. Kressman and Frederick W. Kressman. Jr., Laurel, Miss., assignors of one-half to Continental Turpentine & Rosin Corporation, Inc., Laurel, Miss., a corporation of Mississippi Application January 5, 1942, Serial No. 425,700

9 Claims.

This invention relates to a resinous plastic material and a process of preparing the same and more particularly to a process of reacting rosin with a ligno-cellulosic materia1 at an elevated temperature and obtaining from the reaction a thermo-setting plastic.

An object of the invention is the preparation of a new and improved thermo-setting plastic or resin and the development of an improved process of making the same. Another object is to provide a process for utilizing wood and other ligno-cellulosic materials particularly in the form of residues such as those obtained from the acid hydrolysis of Wood and from the extraction of wood with steam and solvents. Still another object is to provide a process for reacting fibrous li no-cellulosic materials such as wood fibers or particles of relatively low density with rosin to form a resinous material.

Another object of the invention is to provide a process for reacting ligno-cellulosic materials with heated rosin in varying proportions to obtain resinous materials of different characteristics. Another object is to provide a resinous plastic material which is thermo-setting and which may be used as a molding resin or as a coating resin. Yet another object is to provide a resinous plastic material which is highly resistant to alkalies and acids and which is soluble in only a limited number of organic solvents. A further object is to obtain a resinous product of a relatively low melting point which is thermosetting and thus may be readily liquefied and will form a solid product upon the further application of heat.

Other features and advantages of the invention will appear from the following specification and drawing, in which- Figure 1 is a diagrammatic showing of apparatus for carrying out the reaction and Fig. 2 is a sectional view taken along the line 2--2 of Fig. 1.

In the specific embodiment of the invention described herein and referring particularly to the drawing, a furnace or heater ll! of any suitable construction is arranged with a container or drum H of any suitable size and shape supported therein and adapted to be heated by the furnace. The furnace is preferably equipped with a suitable temperature control not shown) which permits careful and accurate adjustment of the temperature within the furnace. A flue l2 extending from the furnace receives the exhaust gas therefrom. If desired, the drum or container ll may be equipped with a jacket (not shown) extending about the outside thereof for receiving the heated vapor of a high boiling liquid. In this Way, the temperature of the drum and the material therein may be accurately controlled during the heating operation and the furnace may be eliminated.

The container II is equipped with an inlet opening M which receives the discharge-end of a tubular conveyor IS, the opposite end of the conveyor being in communication with the outlet I6 of a hopper H. The conveyor l5 preferably carries a screw flight l8 on the shaft l9, the shaft i 9 being driven by any suitable power means. Preferably the screw flight l8 extends to a point closely adjacent the inlet opening 14 but is spaced slightly from the drum ll.

Said drum H is equipped in the lower portion thereof with a suitable outlet 24 controlled by the valve 25. This outlet may be used to remove from the drum the liquid product of the reaction. In the upper portion of the drum II is an outlet 26 which permits' the escape of excess vapors from the container.

Within the drum II is a scraper 20 which is carried by the rotatable shaft 2|, the shaft being driven by any suitable power means. The scraper 20 may be equipped, as shown, with a plurality of scraper blades 21 which pass along the inner periphery of the drum I I.

In the operation of the apparatus, the drum II is partially filled with rosin indicated at 22 and heated to a temperature of approximately 450 F. at which point the rosin in the drum has liquefied. Suitable ligno-ceilulosic material such as wood fibers or particles of relatively low density are introduced into the hopper I! from which they are advanced by the screw conveyor Hi to the inlet M in the drum I l and pass into the drum. The ligno-cellulosic particles form a plug 23 between the inlet Id of the drum H and the end of the screw conveyor [8. The plug of ligno-cellulosic particles in the inlet M of the drum l i serves to seal the inlet to prevent escape of rosin vapor from the drum II through the same. As the screw conveyor I8 is rotated, the plug of wood particles as a whole is advanced, the particles at the discharge end being introduced into the drum I I.

As the ligno-cellulosic material is fed into the drum, the temperature of the rosin is gradually raised and substantially all of the ligno-cellulosic material is added by the time that the temperature of the rosin reaches 550" F. The raising of the temperature of the rosin continues until the mixture of rosin and ligno-cellulosic material in the drum reaches the neighborhood of 600 F.

The scraper 20 is continuously operated during the reaction and serves to intimately mix the particles of the ligno-cellulosic material with the rosin and continuously agitate the mixture. The reaction is continued for a substantial period of time in order to permit all of the ligno-cellulosic material to react with the rosin. The reaction is an endothermic one and requires the addition of a considerable amount of heat to carry it on properly. 'After the materials are mixed the reaction begins and takes up a large quantity of heat. When the reaction mixture no longer takes up substantial quantities of heat the reaction may be considered as being complete or nearly complete. Ordinarily, the reaction will require a period of at least one-half hour and often as long as two or three hours. When the reaction is substantially complete the entire mass in the drum I I is in the liquid state, after which said mass may be removed from the drum ll through the outlet 24 controlled by the valve 25. By means of the invention it is possible to utilize ligno-cellulosic products such as wood fibers which may be in the nature of residues from other operations or processes. For example, the finely divided particles of wood fibers which are obtained from the acid hydrolysis of wood and the wood fibers which have been processed either in steam or organic solvents to remove therefrom the soluble organic -constituents thereof are particularly suitable for the process. Unprocessed fiber or sawdust is not as desirable as these materials but may in some instances be used in the process. It has been found that the reaction m'ay be carried out, for example, with pine shavings and alpha-cellulose. The ligno-cellulosic material should preferably be in the form of finely divided particles. However, if the reaction conditions are very carefully controlled, it is possible to carry out the reaction using particles of a substantial size.

By using the screw conveyor to introduce the ligno-cellulosic material into the reaction chamber, the mixing operation may be carefully controlled. The material should be introduced. slowly in order to permit the ligno-cellulosic material to become mixed with the rosin shortly after it is introduced into the container. It is, of course, desirable to introduce the material as rapidly as possible without forming a doughy mass in the rosin. If the material is introduced too rapidly, this doughy mass will be formed and will prevent the proper mixing and reacting of the ingredients. Nevertheless, in accordance with the present invention the ligno-cellulosic material may be introduced in a very short time,

it being possible to completely mix a large batch in a few minutes under ordinary conditions.

By following the reaction conditions set forth, it is possible to readily incorporate the lignocellulosic material in the liquid rosin without the formation of a doughy mass in the rosin and without any substantial scorching or partial carbonization in the mixture.

Since rosin at a temperature of 450 F. or above possesses a substantial vapor pressure, the chamber during the course of the reaction contains rosin vapor above the liquid rosin. When the wood fibers are introduced into the chamber, they are brought into contact with this vapor before being introduced into the liquid rosin. The rosin vapor being maintained at an elevated temperature serves to preheat the wood fibers while, at the same time, the cooler fib r cause local condensation of the rosin vapor on the same. It may be that the condensation of the rosin vapor on the wood fibers to form liquid rosin facilitates the introduction of fibers into the liquid rosin and the mixing of the same therewith by increasing the density of the wood fibers and by wetting the fibers with the condensed liquid rosin to improve the blending of the fibers with the liquid rosin. V

The wood particles or ligno-cellulose may be added continuously to the heated rosin by means of the screw conveyor until the proper proportions of the reaction ingredients have been obtained. At this point the temperature is preferably raised as rapidly as-possible to a temperature in the range of 600 F.-650 F., preferably between 625 F.635 F. and the mixture maintained at this temperature and continuously agitated until the reaction is substantially complete. hours will be required for the reaction, the time varying substantially with the quantities of ingredients used and with the other conditions of the reaction. The reaction is preferably carried out at atmospheric pressure. a

The exact mechanism of the reaction is not completely known. Since the reaction occurs at a temperature to which both the rosin and the wood particles normally partially decompose, it may be that the reaction occurs between the decomposition products or partial decomposition products of the rosin and ligno-cellulose. At any rate, when the reaction is carried out under the conditions set forth, the materials readily react to form a resinous plastic thermo-setting prodnot.

In carrying out the reaction, the temperature of the mixture in the reaction chamber should be very carefully controlled. The rosin should be heated before the ligno-cellulosic material is introduced. The temperature at which the rosin is initially heated prior to the introduction of the ligno-cellulosic material should be in the neighborhood of 450 F. After the material has been introduced into the rosin the temperature of the mixture should be raised to approximately 600 F. and maintained in the neighborhood of this temperature until the reaction is substantially complete. Preferably, the mixture should be maintained at a temperature of between 625 F. and 635 F. as the reaction proceeds.

In carrying out the reaction various proportions of the ingredients may be used. Preferably in the neighborhood of equal parts of the lignocellulosic material and the rosin are used in the reaction, the proportions being by weight. Since the ligno-cellulosic material, when formed of light wood fibres, may be of a density a low as /20 or Han of that of the rosin, the process in this instance serves to facilitate the incorporation of the fibres in the rosin.

The proportions in which the ingredients are mixed will, to a certain extent, determine the type of product which is obtained in the reaction. For example, a reaction between fifty percent ligno-cellulosic material and fifty percent rosin results in a product which has a melting point of 260 F. On the other hand, when forty-three percent ligno-cellulosic material is reacted with fifty-seven percent rosin, the product has a melting point of approximately 230 ,F., while the product of a reaction of forty-five percent rosin and fifty-five percent ligno-cellulosic material melts at approximately 295 F. In each instance the proportions are by weight and the reaction is Ordinarily, between one-half and two ance and is quite brittle.

anaaac 5 carried on until no Iurthendistillate is obtained from the reaction mixture 'at a temperature at a range of 625 F. and 630 F.

Each of the various products which is obtained in the reaction is subject to a lowering of the melting point if the product is reheated at a higher temperature in the absence of air. For example, the product obtained by reacting parts of the rosin and ligno-cellulosic material, which melts at 260 F., may be reheated at 640 F. to 650 F. in the absence of air to obtain a product which melts at approximately 230 F. In each case the heating at a higher temperature in the absence of air will result in the lowering of the melting point. The operation need not be a reheating operation since the same effect may be obtained by heating the product or the original reaction mixture to 640 F. to 645 F. in the absence of air. The product of the reaction between forty-five percent and fifty-five percent lignocellulosic material, which normally melts at 295 F., may be changed to a 230 F. melting point product by heating the material in the absence of air at a temperature in the range of 650 F. to 660 F.

The products resulting from the reaction are in the form of black plastic resins which are liquid at the reaction temperature. If the product i withdrawn from the reaction chamber while in the liquid condition, it will be found to have the melting point above stated when tested by the ball and ring method.

When the products of the reaction are heated in the presence of air to a temperature above 630 F., preferably in the neighborhood of 650 F. to 660 F., they will gradually solidify to form insoluble infusible masses. The products, therefore, are possessed of thermo-setting properties and are extremely valuable as molding compounds.

The thermo-setting resin which is normally obtained from the reaction in the liquid phase,

may have a melting point of approximately 230 F. and is, therefore, normally solid. The solid resin possesses a black opaque lustrous appear- When fractured the exposed portions of the rosin are brilliant and lustrous.

The reaction product is substantially insoluble in practically all organic solvents with the exception of aromatic naphthas and carbon tetrachloride. Such solvents as parafiinic naphthas, gasolines, greases, oils, etc., do not affect the material. In addition, the resinous material is resistant to organic and mineral acids and to caustic solutions in concentrations up to ten percent.

The reaction product may be used in further reactions to obtain desired materials. It may,

for example, be reacted with drying oils .such as tung oil or linseed oil to form a new type of coating plastic resin as distinguished from molding plastics. For this type of reaction, a mixture of twenty-five percent to thirty percent of the oil with seventy to seventy-five percent of the resinous material is preferably used. The product of such a reaction is soluble in mineral spirits and will produce tough films of high luster and jet black reflection. Such products are extremely useful in the preparation of coating finishes.

The rer'.:ous plastic product of the reaction between .116 rosin and ligno-cellulosic material ...ay be used as a molding resin and is particularly valuable because of its thermo-setting properties. On the other hand, the product may also 6 be used as a coating resin particularly when treated with drying oils and the like. As a coating resin the product is particularly useful in pipe and conduit coverings and the like.

The foregoing specific description has been given for the purpose of illustrating the invention and the means of practicing it. Changes and modifications, therefore, may be made in the process and product as set forth, particularly as to the quantities of the reagents used and as to the conditions of the reactions without departing from the spirit and scope of the invention.

We claim:

1. A process of forming a resinous plastic material comprising heating a body of rosin to a temperature in the range of 450 F.550 F., introducing into the heated body a solid lignocellulosic material, agitating the mixture, and then heating the same to a reaction temperature until the entire mass has liquefied, said reaction temperature being at least approximately 600 and not substantially above 650.

2. A process of forming a resinous plastic material comprising, heating a body of rosin to a temperature in the range of 450 F.-550 F., introducing small particles of wood fibre into the body of rosin, agitating the mixture, raising the temperature of the mixture to 600 F.-650 F., and maintaining the mixture at the raised temperature until the entire mass has liquefied.

3. A process of forming a resinous plastic material comprising, heating a body of rosin at atmospheric pressure to a temperature in the neighborhood of 450 F., introducing into the body small fibrous particles of aligno-cellulosic material, the particles being of relatively low density, intimately mixing the ligno-cellulosic material with the liquid rosin, increasing the temperature of the mixture to ,a temperature in the range of 625 F.-635 F., and maintaining the mixture at a temperature in said range while continuously agitating the same until the entire mass has liquefied.

4. A process of forming a resinous plastic material comprising, heating a body of rosin to a temperature in: the range of 450 F.-550 F., introducing small particles of fibrous ligno-cellulosic material of relatively low density into the heated rosin, said particles being present in the 0 proportion of approximately one part by weight to each part by weight of rosin, agitating the mixture, raising the temperature of the mixture to 600 F.-650 F., and maintaining the mixture at the raised temperature while continuously agi- 55 tating the same for a period of at least one-half hour to "permit the ligno-cellulosic material to react substantially completely with the rosin.

5. A process of forming a resinous plastic material comprising providing a substantially closed 60 container having therein a quantity of heated rosin, the rosin being in the liquid state and at a temperature of approximately 450 F., gradually raising the temperature of the rosin to 550 F. while slowly introducing into the same small 05 fibrous wood particles of relatively low density,

intimately mixing the wood particles with the liquid rosin, raising the temperature of the mixture to a temperature in excess of 600 F., and

below the decomposition temperature of the res- T0 inous reaction products and maintaining the mixture at a temperature in excess of 600 F. while agitating the same for a substantial period of time to permit the entire mass to liquefy.

6. A process of forming a resinous plastic ma- 75 terial comprising, providing a body of heated rosin at a temperature in the range of 450 F.- 550 F., introducing into the body small particles 01' ligno-cellulosic material, intimately mixing the ligno-cellulosic material with the rosin, raising the temperature of the mixture to 600 F.-650 F., and maintaining the mixture at the raised temperature for a period of at least several hours while simultaneously agitating the mixture.

7. A process of forming a resinous plastic material comprising, providing a body of heated liquid rosin, introducing into said body small particles of a ligno-cellulosic material, raising the temperature of the mixture to a temperature in excess of 650 F., and below the decomposition temperature or the resinous reaction products, maintaining the mixture at the raised temperature for a substantial period of time until the reaction between the ligno-cellulosic material and the rosin is substantially complete, the mix-- ture being maintained at the raised temperature in the presence of air.

8. A process which comprises heating rosin to substantially the melting point of pure rosin, mixing the resulting molten material with the ligno-cellulosic material .in approximately equal proportions by weight, then heating the mixture to a reaction temperature above 800 F. and not substantially above 650 E, and maintaining the mixture at that temperature for a period oi at least approximately one-half hour.

9. The method as set forth in claim 8, in which the reaction is carried out at a temperature oi GOO-635 F., and the reaction product is then heated in the absence of air at a temperature above 640 F.

FREDERICK W. KRESSMAN. FREDERICK W. KRESSMAN, JR. 

